At present, lighting systems as applied in e.g. museums or shops comprise a plurality of light sources for illumination of different objects or locations. As an example, each object or location can be illuminated by a subset of the light sources of the lighting system. In order to control the subset of light sources or lighting devices, state of the art solutions use a lighting network whereby each of the controllable lighting devices can be addressed individually by a (master) control unit. This may results in a comparatively large number of channels to be individually addressed. As an example, assume a lighting system comprising 100 lighting devices (e.g. LED lighting units), each having 4 controllable colour groups. Addressing each colour group would thus require up to 4*100=400 lighting channels. Controlling, this many individually controllable channels may require a complex, voluminous, costly lighting controller or control unit. Updating such a large number channels, e.g. at a refresh rate of 20 ms may lead to a high data rate, as each 20 ms all lighting channels of the lighting devices are addressed by the controller or control unit.
A further disadvantage of the state of the art lighting controllers is that they are not redundant (prohibitive out of cost, volume, or complexity), which is an issue when used for general lighting which must be dependable and preferable redundant and easy to fix on potential device failures. Especially since the actual individual fixture setting are only known by the master lighting controller, this makes replacing this central control not a task that the average user can perform, prohibitive for general use of this kind of intelligent lighting (it generally now demands a skilled, informed and manual-reading user as well). The central control concept is also prohibitive for multi-location control due to the central (non-redundant) knowledge.
Furthermore, existing lighting protocols sending out 400 lighting channels also requires a bandwidth that is not only costly on the controller side, but also for each individual lighting device's network interface. High bandwidth network interfaces are also a significant size constraint in the existing lighting devices. The currently required bandwidth also rules out certain network interface physical layers that would be easier and more cost effective to implement than e.g. the RS485/DMX standard that is often used for this kind of application. A sufficiently lower bandwidth would enable reliable long distance power line communications. In addition, in principal high bandwidth communication also requires more transmit and receiver physical layer dissipation than a lower bandwidth solution would require.
Furthermore, it is often observed that such a centralised (master) control unit is often provided with a non-intuitive and complex user interface. In order to control/install or configure a group or subset of lighting devices for a particular situation (e.g. for illumination a particular location or object) the state-of-the-art centralized lighting network (i.e. controlled by a master control unit) often does not support, in a cost-effective manner, a way of local (e.g. standing at object or location of interest) setting or calibration of the required lighting effect. Preferably a user would like to be close to a certain scene/location for close observation and feedback for the required lighting effect or illumination conditions.
In view of the above, it is an object of the present invention to provide a control unit for controlling a configuration of light sources and a lighting system that overcomes, at least partly, one of the drawbacks of lighting system control units and lighting systems as known in the art.